应用生态学报最新文献

The transpiration-to-evapotranspiration ratio (T/ET) characterizes the proportion of vegetation transpiration in evapotranspiration and is of great significance for understanding the role of vegetation transpiration in ecosystem water cycling. We utilized multi-source data to analyze the variations and driving factors of T/ET in three ecosystem types of Northeast China from 2001 to 2020, including forests, croplands, and wetlands. The results showed that the interannual variation of T/ET in forests, croplands, and wetlands exhibited a slight upward trend from 2001 to 2020, with annual increase rates of 0.0006, 0.0037, and 0.0009, respectively. T/ET exhibited a unimodal pattern during the growing season, rising from May, peaking in July and August, and then declining. The proportions of areas showing an upward trend in T/ET in forest, cropland, and wetland ecosystems were 59.7%, 84.7%, and 55.1%, respectively. During the growing season, the T/ET ratios of forest ecosystems in the southeastern part of the study area, cropland ecosystems in the central part, and wetland ecosystems in the southern part were all higher than those of the same ecosystem type in other regions. The dominant biological driving factors for T/ET changes in the three ecosystem types were gross primary productivity (GPP) and solar-induced chlorophyll fluorescence, but with differences among different ecosystems. In forest ecosystems, the explanatory power of relative humidity, precipitation, and minimum temperature was higher than that of other environmental factors. In croplands, the effects of saturation vapor pressure deficit, relative humidity, and precipitation were more significant. In wetlands, T/ET was mainly influenced by net radiation, precipitation, and minimum temperature. Among the combinations of biological and environmental factors influencing the changes in T/ET across different ecosystems, gross primary productivity and relative humidity constituted the most explanatory combination.

Exploring the landscape ecological risk and ecological protection and restoration strategies in the dry-hot valley region of the Jinsha River Basin is of great significance for promoting the high-quality development of the Yangtze River Economic Belt. With Chuxiong Yi Autonomous Prefecture as the research area, we evaluated landscape ecological risk and determined its ecological background using the InVEST and Zonation models, and further constructed the ecological security pattern by integrating the ecological characteristics of dry-hot valley regions to guide the formulation of ecological restoration strategies, thereby ensuring regional ecological security. The results showed that there is a patchy and locally aggregated pattern of ecological risks , with high-risk patches being concentrated in dry-hot valley areas and urban expansion zones and low-risk areas being mainly found in mountainous forest regions. With an area threshold of 5 km², we identified 154 ecological sources, accounting for 19.5% of the total area of the prefecture, mainly distributed in Ailao Mountain, Baicao Ridge, and Wumeng Mountain with large forest area. We extracted a total of 241 ecological corridors with a combined length of 2779.49 km, which showed a distribution pattern of shorter corridors around the periphery and medium-to-longer corridors in the interior. There were 173 ecological pinch points with a total area of 57.87 km², and the area of the largest pinch point was 13.44 km². The number of ecological barriers was 101 with a total area of 172.14 km², mainly distributed in areas heavily affected by human activities such as railways and expressways. Based on ecological sources, combined with the connectivity direction of ecological corridors and the resistance surface, we constructed an ecological security pattern of "three zones, four belts, and multiple points", and proposed corresponding ecological restoration strategies. This study would provide theoretical support for ecological protection and sustainable development in Chuxiong Yi Autonomous Prefecture and offer reference value for ecological protection and restoration in dry-hot valley regions.

The correspondence between topsoil pollen and modern vegetation is critical for reconstructing paleove-getation and paleoenvironment from palynological fossil records. Taking the Tianchi Lake watershed in the karst trough valley of eastern Sichuan Basin as a case, we explored the correspondence between pollen assemblages and current vegetation across seven land use types: cultivated land, abandoned cropland, shrublands, mixed forest, bamboo forest, pomelo orchard, and plum orchard. The results showed that the proportion of coniferous trees pollen was the highest (57.1%), followed by herbaceous plant pollen (25.7%), while that of fern spore was relatively low (22.8%), and broad-leaved tree pollen had the lowest proportion (17.2%). The proportion of broad-leaved tree pollen deviated from the typical subtropical evergreen broad-leaved forests. Such discrepancy might be attributed to the dilution effect of high-yield pollen on low-yield pollen and the inherent characteristics of the pollen. The topsoil pollen assemblages from different land use types showed a strong correspondence with the modern vegetation, particularly in terms of constructive and dominant species. The PCA results showed that pollen could distinguish the seven land use types. Among these, cultivated land and bamboo forests showed weaker correlations with Poaceae and Amaranthaceae, possibly due to soil disturbance from cultivation and the thick humus layer beneath bamboo forests. The representativeness of topsoil pollen varied across species or genera, with Pinus over-represented and deciduous Quercus and Poaceae under-represented. There were significant differences in average spore and pollen concentration among land use types, indicating that spore and pollen concentrations could reflect the intensity of human activities. The topsoil pollen assemblages in the Tianchi Lake watershed broadly reflected the overall characteristics of current vegetation. However, the interpretation of pollen assemblages required comprehensive consideration of various influencing factors, including soil erosion and palynological preservation conditions.

The fragmentation of habitat patches is rising due to economic development and urban expansion. The systematic design of an ecological network can link fragmented habitat patches, improve landscape connectivity, augment ecosystem service capabilities, and foster the robust development of the ecosystem. We employed the methods of morphological spatial pattern analysis and landscape connectivity analysis to identify ecological source areas, and utilized the minimal cost resistance model through the superimposition of multiple factors to construct the ecological resistance surface. Combining circuit theory to extract ecological corridors, grips, and obstacle points, we constructed the ecological network of the Yellow River Delta Efficient Ecological Economic Zone by using the "source-corridor-node" paradigm and analyzed the structure and resilience of this network. We identified 41 ecolo-gical sources regions, with a total area of 2994.45 km². We extracted 21 first-level ecological corridors, 26 second-level ecological corridors, and 18 third-level ecological corridors, with a total length of 1655.42 km and an average length of 25.46 km. We identified 127 ecological pinch points with a total of 32.92 km² and 20 ecological obstacles, corresponding to regions that required key ecological conservation and restoration work. The ecological network closure index was 0.74, the connectivity index was 2.32, and the connectivity index was 0.83, indicating a relatively comprehensive ecological network structure. The initial values of the connectivity robustness and vulnerability robustness of the ecological network were 0.98 and 0.42, respectively. The critical values for the stability of the ecological network function were an edge failure ratio of 45% and a node failure ratio of 20%. Generally, our findings have significant reference and guiding value for the landscape fragmentation management, biological habitat protection, development of ecological security, and ecdogical network evaluation in the Yellow River Delta Efficient Ecological Economic Zone.

The North Creek Basin of the Jiulong River is located in a typical subtropical monsoon climate zone, characterized by distinct hydrological seasonality. However, systematic research on the temporal and spatial variations of its fish community structure and the underlying driving mechanisms remains lacking. To understand spatiotemporal patterns of fish communities and the driving factors in the North Creek Basin of the Jiulong River, we examined fish communities from 18 sampling sites in March (spring, the dry season) and September (autumn, the wet season) of 2021. A total of 58 fish species, belonging to 49 genera, 16 families and 4 orders, were collected throughout the year. The majority of the specimens were cyprinids, followed by flathead loaches and gobies. The dominant species in the dry season included Coptodon zillii, Rhinogobius giurinus, and Oreochromis niloticus. The dominant species were C. zillii and O. niloticus in the wet season. Species richness and Shannon index were significantly lower in the dry season than those in the wet season. Spatially, fish abundance in the mainstem was significantly lower than that in the tributaries. Redundancy analysis results indicated that water depth and dissolved oxygen were the key environmental factors influencing fish abundance and biomass patterns during the dry season. During the wet season, water temperature, dissolved oxygen, and permanganate index were the key factors affecting fish abundance and biomass patterns. This study revealed the spatiotemporal patterns and influencing factors of fish communities in the North Creek Basin, providing a scientific basis for fish diversity conservation and ecosystem health maintenance in subtropical rivers.

Soil aggregates are the basic units of soil structure and play a crucial role in maintaining soil ecological functions. Intercropping has great potential to promote the formation and stabilization of soil aggregates. However, there is a lack of systematic summary on the mechanisms by which intercropping systems affect the structure and function of soil aggregates. We summarized the rhizosphere processes influencing soil aggregate formation, sorted out the effects and action mechanisms of root structure and morphology, root exudates, rhizosphere microorganisms, soil fauna, and rhizosphere physical processes on soil aggregate formation, and explored the potential processes and mechanisms by which intercropping drives soil aggregate formation by affecting root structure and morphology, root exudates, and rhizosphere microorganisms. Additionally, we reviewed the impacts of intercropping on organic carbon, nutrient content and availability, and microbial community characteristics in soil aggregates with different particle sizes. Finally, we prospected the research directions regarding the regulation of soil aggregate structure and function by intercropping, emphasizing that efforts should be strengthened in the following aspects: quantitative research on the process of soil aggregate formation regulated by intercropping; the effects of intercropping on functional microbial communities at the aggregate level and the corresponding regulatory mechanisms; the spatial and temporal scales of intercropping's impacts on soil aggregate structure; and the development of intercropping technologies and models based on the directional cultivation of macroaggregates.

Constructing a scientifically sound ecological compensation mechanism is a crucial approach to harmonize regional ecological conservation with socio-economic development, which has significant implications for the sustainable use of ecosystem services. Based on multi-source remote sensing data, we quantified the supply and demand of ecosystem carbon sequestration service in Fujian Province. With the supply-demand ratio, hot/cold spot analysis, and breakpoint-field strength models, we examined the spatial flow features (direction, rate, and flux) of carbon sequestration services in Fujian from 2000 to 2020, and further quantified ecological compensation with considerations of payment capacity and willingness to pay. The results showed that both the supply and demand of ecosystem carbon sequestration in Fujian Province increased significantly between 2000 and 2020. The supply showed a northwest high and southeast low distribution, while the spatial distribution of demand exhibited the opposite pattern. There was a mismatch between dominant supply and demand for ecosystem carbon sequestration services in Fujian Province, which was worsening over time. Coastal areas typically exhibited a supply-demand deficit with low supply-high demand and high supply-high demand, while other regions mostly showed a supply-demand surplus with high supply-low demand. In 2020, the ratio of counties between the supply region and the demand region for ecosystem carbon sequestration was 9:32, showing a spatial pattern of west supply and east input. The total carbon outflow from the supply region was 4264107 t, with the largest outflow from Zhangping City and the largest inflow to Changtai District. The payment to the compensated areas should been 182 million yuan, but the actual expenditure was 91.16 million yuan. Changtai District had the highest actual expenditure, while Zhangping City had the highest actual income.

Diarrheal shellfish toxins (DSTs) are a type of liposoluble toxins produced by toxic algae in the ocean, with main components of okadaic acid (OA), dinotricin-1 (DTX-1), and dinotricin-2 (DTX-2). They can accumulate in shellfish through food chain. Human consumption of toxic shellfish can have adverse effects on health. Therefore, conducting DSTS detection can effectively ensure food safety. Base on the principle of competitive enzyme-linked immunosorbent assay (ELISA), referring to the seed growth method, we prepared goldnano rods using gold nanoparticles (AuNPs), and conjugated them with okadaic acid antibody-horseradish peroxidase (OA-HRP) to form nanoprobes, which together established a novel ELISA technology of goldnano rods labeled OA-HRP. The technology presented significant detection advantages with a detection limit of 2.32 ng·mL^-1, a quantification limit of 2.97 ng·mL^-1, and a sample recovery rate of 85.2% to 117.8%. Both the intra-batch and inter-batch varia-tion coefficients were below 20.0%. The proposed method demonstrated high specificity for okadaic acid (OA), dinophysistoxin-1 (DTX-1), and dinophysistoxin-2 (DTX-2), with no cross-reactions observed against six other lipophilic toxins-azaspiracid-1, azaspiracid-2, and azaspiracid-3 (AZA-1, AZA-2, AZA-3), pectenotoxin-2 (PTX-2), yessotoxin (YTX), and homo-yessotoxin (hYTX). Moreover, it showed good correlation with the determination results of liquid chromatography-tandem mass spectrometry (LC-MS/MS). The goldnano rods labeled OA-HRP direct ELISA method established here significantly improved the detection sensitivity of DSTs, which could be used for rapid quantitative detection and analysis of DSTs in seafood, with significant application prospects.

To investigate the impact of meteorological droughts in different seasons on tree radial growth, we analyzed the correlations between radial growth of Abies recurvata at three altitudes (3400, 3800, 4000 m) and clima-tic factors along with resistance, recovery, and resilience to different seasonal droughts (spring 1998, summer 2008, consecutive spring-summer 2003) in Miyaluo of Sichuan, utilizing tree-ring width index and standard chronology. The results showed that at low altitude (3400 m), chronologies showed significant positive correlation with Palmer drought severity index (PDSI) from previous September to current June, and significant negative correlation with current January monthly mean maximum temperature. At middle and high altitudes (3800, 4000 m), significant positive correlation occurred with current April PDSI and precipitation. The resistance of radial growth at three altitudes to consecutive spring-summer drought and spring drought was significantly lower than that to summer drought, while the resilience to consecutive spring-summer drought at middle and high altitudes (0.95, 0.94) was significantly lower than that to spring drought (1.13, 1.23) and that to summer drought (1.17, 0.99). Under consecutive spring-summer drought, the resistance at low altitude (0.57) was significantly lower than that at high altitude (0.78), the recovery and resilience were significantly higher than those at high altitude, and the resistance at middle altitude was significantly lower than at high altitude. Under spring drought, the resistance and resilience at low and middle altitudes were significantly lower than at high altitude. Under summer drought, the recovery and resilience at low and high altitudes were significantly lower than at middle altitude. In summary, the radial growth of A. recurvata was most severely impacted by consecutive spring-summer drought. Populations at low altitudes demonstrated significantly weaker resistance, while those at high altitudes were limited by reduced recovery capacity, leading to lower growth resilience compared to low-altitude populations.

Since the 19th century, as Western botanical expeditions extended into the hinterland of Asia, Southwest China has gradually become an important region for plant collection. However, systematic quantitative analyses of such plant collection activities are lacking. We reviewd the plant collection activities of eight renowned Western botanists in Southwest China from 1840 to 1949, as well as the taxonomic composition of the collected plants. A total of 56273 plant specimens were examined in this study, belonging to 7940 species, 1742 genera, and 304 families. Temporally, the sheets of specimens collected peaked during the thirty years from the late 19th century to the early 20th century. Spatially, the collections were concentrated in the Hengduan Mountains and the Yunnan-Guizhou Plateau, particularly in middle- and high-altitude regions. The most frequently collected plants belonged to families such as Ericaceae, Rosaceae, and Asteraceae. The plant collection activities of Western botanists in Southwest China provided specimen resources for taxonomic research, and offered valuable scientific references for advancing regional biodiversity conservation.